feat(contacts): store contact submissions

apps/contacts/api/serializers.py

@@ -0,0 +1,43 @@
+from rest_framework import serializers
+
+from apps.contacts.models import ContactSubmission
+
+
+class ContactSubmissionCreateSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = ContactSubmission
+        fields = (
+            "first_name",
+            "last_name",
+            "email",
+            "mobile",
+            "message",
+        )
+
+    def validate_mobile(self, value):
+        clean_value = value.strip()
+        if len(clean_value) < 8:
+            raise serializers.ValidationError("Enter a valid mobile number.")
+        return clean_value
+
+    def validate_message(self, value):
+        clean_value = value.strip()
+        if len(clean_value) < 10:
+            raise serializers.ValidationError("Message must be at least 10 characters.")
+        return clean_value
+
+
+class ContactSubmissionResponseSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = ContactSubmission
+        fields = (
+            "id",
+            "first_name",
+            "last_name",
+            "email",
+            "mobile",
+            "message",
+            "status",
+            "created_at",
+        )
+        read_only_fields = fields